1. Field
The field is web conferencing, specifically the application of time-shifting presentation techniques to the field of web conferencing.
2. Prior Art
Web conferencing systems can be used hold meetings and give presentations where participants are in remote locations. Web conferencing systems allow participants to share content with and observe content from other participants. Typical types of content include screen video data, camera video data, audio data (through computers and through telephones), chat data, documents, and the like
The current generation of web conferencing systems is focused primarily on real-time interaction. That is, participants join a virtual meeting at a designated time and are able to present and observe in real time (hereafter synchronously). Secondarily, many web conferencing systems can record the meeting. This allows a participant to observe the content of the meeting after the meeting has concluded.
However current web conferencing systems are unable to enable participants to asynchronously observe a live meeting, i.e., observe a previously recorded part of the meeting while the meeting is still in progress. This is undesirable for several reasons. First, if a participant joins a meeting five minutes late, their only choices are to either observe real-time and simply miss the first five minutes, or wait until the entire meeting has concluded to watch the entire recorded content or a selected part of it. Second, if a participant is observing real-time there is no way for them to pause the content to deal with an interruption, or to easily replay a portion of the content to repeat something they missed. Third, if a participant is observing in real-time and the presenter is moving too quickly, there is no way for the participant to slow the presentation.
A key struggle with using existing web conferencing systems is the organization and scheduling required to ensure that all participants are available and connected before the presentation begins. This leads to great inefficiencies, because some participants will simply have to wait for the rest of the participants to join, and some participants may miss part of the presentation or have to wait until the presentation has completed to observe it in its entirety.
In a separate field, commercial digital video recording services and associated equipment, such as one sold under the trademark TiVo by TiVo, Inc, Alviso, Calif., have paved the way in providing live time-shifting capabilities for television viewing and have begun to affect consumers' expectations. Prior to digital video recorders (DVRs), consumers had limited control over their viewing experience. Consumers could either watch a television show in real-time, or with devices like video cassette recorders they could watch a recorded version of the show after the whole show had finished.
DVRs have empowered consumers by allowing them to time-shift real-time television content.
In yet another field, algorithms have been devised to time-scale manipulate audio content with high fidelity reproduction. These algorithms allow an audio stream to be played back at a faster or slower rate while maintaining other perceived aspects of the audio, such as timbre, voice quality, and pitch.
Audio time-scale modification techniques have been applied to applications such as voice-mail and dictation tape playback, post synchronization of film and video, and playback of recorded content. These techniques have also been employed in adaptive buffering schemes for streaming audio (to speed up or slow down audio playback to maintain an optimal buffer length).